Transformer.



J. E. MATEER. TRANSFORMER.

APPLICATIQN FILEDDEC. 18. 1914.

1,249,800.. I Patentgd Dec. 11,1917.

ATTOR N EY UNITED STATES PATENT OFFICE.

JESSE E. MATEER, OF'WILKINSI BURG,PENNSYLVANIA, ASSIGN OR TO WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TRANSFORMER.

Application filed December To all whom it may concern:

Be it known that I, Jessa E. MATEER, a

citizen of the United States, and a, resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Transformers, of which the following is a specification.

My invention relates to electrical transformers, and it has special reference to means for insulating the high-tension coils thereof from the core members, the end frames, the cooling coils and the inclosing tankg in which the transformers may be dispose In transformers adapted for very highvoltage service conditions, such as 100,000 to 150,000 volts, it is highly important to insulate, adequately the high-tension coils so as to insure uninterrupted service conditions for the transformers. Because of the difficulty in precluding the flow of leakage currents from the high-tension coils to .the conducting low-potential bodies adjacent to the coils, such as the cooling coils, the end frames, the core members and the transformer tanks, without the use of a large amount of expensive insulating material, it has heretofore been necessary to unduly lengthen the tanks in order to substantially increase 'the leakage distances between the high-tension coils and theconducting. low potential bodies adjacent thereto. The use of these large-tanks for increasing the leakage distances between the high-tension coils and the cooling coils and thewalls of the tanks requires large amounts of insulating and cooling fluids, such as transformer oil, into which the active parts of transformers are usually immersed. Such tanks are also very heavy and cumbersome thereby rendering it diificult to transport them.

By means of my invention, I provide an insulating structure for the high-tension coils of a transformer which will so thoroughly insulate them as to insure reliable and permanent operation of the transformer, and, at the same time, permit the use of a transformer tank the length of which will be considerably less than that heretofore deemed advisable for a like transformer.

For a better understanding of the nature and scope of my invention, reference may be had to the following description and the Specification of Letters Patent.

Patented Dec. 11, 1917. 18, 1914. Serial No. 877,880.

accompanying drawing in which Figure 1 1s a view, somewhat diagrammatic, of an assembled transformer embodying a form of my invention, Figs. 2, 3 and 4 are detail views of the insulating structure interposed between the high-tension coils and the low potential conducting members of the transformer. Figs. 5 and 6 are detail views of the insulating members which I interpose in the leakage current paths from the hightension coils.

In Fig. l, current-carrying coils 1, of a usual type of construction, embrace magnetizable core members 2 which are positioned upon an end frame 3 that is placed on the bottom of. a tank 4.. The tank 4 contains a body of insulating and cooling fluid 5, and is provided with outlet bushings 6 through which the high-tension leads of the transformer extend. The cooling fluid 5 is cooled by meansof the cooling coil 5 through which cold water is usually circulated. The coil 5 is in relatively close proximity to the upper edges of the hightension coils 1. The coils 1 are insulated from the core members 2 by means of insulating barriers 7 and 8 which are disposed at right angles to each other. It is essential that the insulating and cooling fluid 5 freely circulate through ducts interposed between adjacent current-carrying coils ,1, and, for this reason, it is impossible to entirely inclose the current-carrying coils 1 in an insulating casing. At the same time, the coils .1 must be thoroughly insulated from the core members 2, the end frame 3, the cooling coil 5 and the tank 4, to preclude the flow of leakage currents. To this end, I have provided aplurality of superposed and spaced insulating mem-. bers 9 which are bent into L shape and are so interleaved with the insulating barriers 7 and 8 as to substantially increase the length of the leakage paths between the current-carrying coils 1 and the low potential conducting members in proximity thereto. The insulating members 9 do not entirely bridge the open ends of the hollow rectangular structure comprising the insulating barriers 7 and 8, but are separated into two groups at each end thereof to provide openlngs 10 through which the insulating fluid 5 may circulate.

In Figs. 2, 3 and 4, I have shown, in de- L-shaped angle pieces.

tail, the insulating structure substantially inclosing the current-carrying co1ls l, F1g..

2 being a front view, partially in section, of a portion of the insulating structure, Fig. 3 being sectional view thereof, taken along the llne G-D-of Figs. .2 and 4, and

Fig. 4 being a top view of aportion of the structureshown in Fig. 3. sion'coils l'are' The high-tenarranged in this instance as shown in Fig. .3, anordinary insulating barrier 11. being "interposedtherebetween. A group of insulating barriers 7 .arranged in' parallel relationship with the barrier 11, are dlsposed on opposite sides of the coils 1, the insulating barriers? comprising a' plurality of laminae in groups of two,

made of any suitable insulating material,

such as fuller-boards The insulating membets 9 are interleaved with thebarriers 7 and spacedfrom, and superposed upon, one

another so as to provide a series of overlapping insulatlng extensions asshown in Figs. 2 and 3. As indicated 1n F 1g. 1, one

end of the transformer winding 1 is in close proximity to the adjacent end frame 3. In

"order to increase the length'of the leakage 'paths between the coils' -1 and the end frame 3, the core member- 2,

5, I interpose the insulating members 9 which provide a high-resistance leakage path of considerable length. between the aforementioned members, as explained above.

- As shown in Figs. 5 and 6, the insulating members 9 are-formed of angle pieces of material that are bent into L-shape formations. The material from which these pieces side of 'one leg of these forms to be interleaved with the laminae 8, and permits the other side to be entirely interleaved with the laminae 7 that are rounded at their corners to conformwith the rounded bends of. the

sembly is clearlyshown in Fig. 2-which is a View along the line A-B of Fig. 4:. 'As

shown in Fig.3, adjacent groups of laminae 7 are thus provided with groups of oppositely andinwardly-extending angle pieces 9. The spaces between adjacent groups of these L-shaped pieces 9 are bridged by insuating laminae 9 In combination with the laminae 8, the foregoingstructure provides an inclosure for the coils 1, but itisj impor tant that the groups of insulating members- 9, that inclose the opposite sides of the coils l in the manner indicated above and shown particularly in Fig. 4, be spaced from each other in order to provide the opening'slO for the circulation of the insulating fluid 5.

Moreover, the insulating members 9 areso interleaved with the insulating barriers 7 and 8 as toprovide a substantially homogen'eous inclosing casing for the coils 1 without affecting'the di-electric strength of the barriers 7 and 8. In this way, the curnaaaaoo vtances from all of and the cooling coil.

1s made is relatively thin which permits one.

This method of asrent-leakage paths from the coils l are lengthened and, moreover, their resistance is greatly enhanced and no impediment is offered to the circulation of the insulating and cooling fluid 5 because the openings 10 provide for thecirculation of the oil 5.

By referring to Fig. 2, it will be noted versely of the plane of the openings 10, are

spaced from one another suflicient distances to preclude the leakage currents from the coils 1 from flowing in a straight and direct path to the low-potential members of the transformer, namely, the end frame 3, the

I cooling coil 5 and the tank 4. As a conseformer members. In other words, the pe-' ripheral walls'of thefopenings 10 are designed to obstruct the direct flow of leakage currents to the low-potential members by making said walls of transversely-extending 'and spaced insulating laminae each of which interposes a long high resistance leakage path tothe flow of the leakage currents.

.Care must be exercised in the manufacture of the members 9 that the dielectric strength of the material from which they are made is not decreased. To this end, it is important not to fracture-the material by using right angle bends opposed to the grain of the insulating material in shaping it to the proper "form.

While I have shown and described in detail one embodiment of my invention, it will be apparent to those skilled in the art that many modifications may be made without departing from the spirit and scope of the appended claims.

I 'claim'as my invention:

1. In a transformer the combination with current-carrying coils,- a .magnetizable core member therefor, and laminated insulating barriers'interposed between said coils and core member, of a containing tank for the colls and-core member, and bent insulating members of l... shape interposed in the-leakage paths between the coils and the core member and containing tank, one end of the said L-shaped insulating members engaging said insulating barriers and the other end projecting between the said coils and the containing tank. w

v 2. In a transformer, the combination with current-carrying coils andv a containing tank that the superposed members 9, and especially the portions thereof that extend transtherefon'of'superposed and spaced insulatbeing adapted to receive a body of insulating and cooling fluid, and an insulating casing substantia ly inclosing said coils to in-A sulate them from the core'and said containing tank, the insulating casing being provided with top and bottom, centrally disposed openings to permit circulation of the cooling fluid, the peripheral walls of which constitute a, series of superposed and spaced laminae to thereby increase the leakage dis tances between the coils and the containing tank.

' 4. In a transformer, the combination with current-carrying coils, a magnetizable core member therefor, and insulating laminae interposed between thecoils and the core member, of a containing tank for the coils and the core member, and bent insulating members of L shape which are superposed upon, and spaced from, vone another, corresponding ends of said members being interleaved with said insulating laminae and the other ends being disposed transversely to the lealiage paths between thecoils and said tan 5 5. In a trans-former, the combination with current-carrying coils, a magnetizable core member therefor, and insulating barriers j between the coils and the core member, of a containing tank for the coils and core members, and superposed and spaced insulating laminae transversely interposed across the,

, subscribed leakage paths between the coils and said core and tank members;

6. In a transformer, the combinatlon with current-carrying coils, a magnetizable core member therefor, and insulating barriers between the coils and the core member, of a containing tank for the coils and core membars which is adapted to receive a body of cooling and insulating fluid, and superposed and spaced insulating laminae interposed in the leakage paths between the coils and said core and tank members, the spaced insulating lamina being provided with top and bottom openings in order to permit unobstructed circulation of the insulating fluid.

7. In a transformer, the combination with current-carrying coils, a magnetizable-core member therefor, of a containing tank for the coils and the core member, said tank being adapted to receive a body of insulating and coolingfluid, an'insulating casing substantially inclosing said coils to insulate them from the core, and superposed and spaced insulating laminae disposed in the path of circulationof the cooling fluid and interposed in the leakage paths between the coilsand said core and tank members.

8. In a transformer, the combination with;

current-carrying coils, a core member and a oontalning casing therefor, of superposed;

and spaced insulating laminae transversely interposed across the leakage paths between the coils and the said core and casing.

In testimony whereof, I have hereunto my name this 9th day of Dec.

JESSE E. MATEER. Witnesses M, F.'MI' ISCHUCH, I B. B. Hines; 

